Gas Phase Characterization of Supramolecules Using Cross-Sectional Areas by FTICR and Sustained Off-Resonance Irradiation Collision Induced Dissociation Techniques in a Fourier Transform Ion Cyclotron Resonance Mass Spectrometer
In my dissertation, I use a Fourier Transform Ion Cyclotron Resonance Mass Spectrometer (FTICR-MS) to investigate supramolecules. Cross-sectional areas by Fourier transform ICR (CRAFTI), a novel technique for measurements of collision cross sections by FTICR, is demonstrated for the first time. The CRAFTI method measures the total "dephasing cross section" for removal of the ions from the coherent packet in the FTICR cell, including contributions not only from momentum transfer but also from reactive collisions including those leading to collisional dissociation. Experimental CRAFTI collision cross sections correlate linearly with theoretically computed results and with results obtained using ion mobility measurements. Different collision gases, including Xe, N2, Ar, and SF6, are all appropriate for the CRAFTI technique when the experiments are done at proper kinetic energies. The CRAFTI technique was applied to characterize the molecular shape of complexes of alkyl mono- and n-alkyldiamine with cucurbit[n]uril in the gas phase. The CRAFTI results are consistent with corresponding computational geometries. The CRAFTI technique was combined with SORI-CID (sustained off-resonance irradiation collision induced dissociation) for characterization of complexes of α,ω-alkyldiammonium with cucurbit[n]urils (n=5, 7 and 8) and cucurbituril derivatives. The results demonstrate that for bigger cucurbiturils, the complexes have the alkyldiamine tails threaded through the cavity of the host; for smaller cucurbiturils, the complexes have the tails of the alklydiamines external to the portal of the host.Capping molecules for larger CBn to form larger containers were also investigated. Using SORI-CID methods, CB7, a bigger cucurbituril cage, was found to form a more stable complex with Gu+ (guanidinium). Several neutral guests (benzene, fluorobenzene and toluene) were trapped in CB7 cavity to form inclusion complexes.
College and Department
Physical and Mathematical Sciences; Chemistry and Biochemistry
BYU ScholarsArchive Citation
Yang, Fan, "Gas Phase Characterization of Supramolecules Using Cross-Sectional Areas by FTICR and Sustained Off-Resonance Irradiation Collision Induced Dissociation Techniques in a Fourier Transform Ion Cyclotron Resonance Mass Spectrometer" (2012). Theses and Dissertations. 3292.
FTICR-MS, CRAFTI, SORI-CID, Supramolecular Complexes